The present invention relates generally to lubrication systems for compressors and more specifically to such lubrication systems including means for preventing lubricant entrained foreign particles from being circulated through the bearings of the compressor.
Refrigeration compressors generally provide a motor drivingly connected to one end of a crankshaft rotatably journaled in a housing and have compressor means connected to the opposite end thereof. Passages are provided in the crankshaft for supplying lubricant from a sump to each of the bearings supporting the crank. In order to insure extended trouble-free operation of these refrigeration compressors, it is extremely important to insure an adequate flow of lubricant to these bearings which is as free as possible from foreign particles which may cause excessive wear or scoring of the working surfaces. While these refrigeration compressors are generally hermetically sealed, foreign particles may enter the lubricant from a variety of sources such as during manufacture of the compressor or other system components, from wearing surfaces, or even during installation. Accordingly, it is desirable to provide a lubrication system having means for separating these foreign particles from the lubricant as it is pumped to the bearings.
In one such separating arrangement of which applicant is aware, an axial thrust bearing is provided with a radial groove which periodically communicates with an extension of an eccentric oil passage provided in the crank into which the foreign particles settle thereby allowing the particles to be returned to the oil sump. However, this system may not be fully effective as the extension of the oil passage is brought into communication with the radial groove only once for a brief period during each revolution of the crankshaft. This may be insufficient time to allow the particles to be flushed out of the extension thus allowing the particles to build up to a level where they are carried by the oil flow to the bearings or possibly even clog the extension passage thus totally defeating the system. Further, when only small quantities of particles are present, the repeated unrestricted flow of lubricant through this radial passage even for brief periods may result in oil starvation of the upper bearings.
The present invention, however, overcomes these problems in providing a lubrication system having means for separating foreign particles from lubricant flowing to the bearings which allow such particles to be continually flushed from the flow area. An axial thrust bearing is provided with a plurality of passages which communicate with a collection area provided in the lower bearing housing. Thus, the particles may pass out of the lubricant flowpath through numerous routes. Passage means are also provided in the lower bearing housing to allow excess lubricant to continuously flush at least a portion of the particles from the collection area back to the oil sump thus preventing any accumulation which could result in clogging of the system. Further, as neither the oil pump nor the eccentric supply passage communicates directly with the particle disposal passage, oil pressure is maintained substantially constant through the entire rotation of the crankshaft thus insuring an adequate continuous supply of oil to all the bearings. Also, an extension of the passage means is adapted to cooperate with a portion of the axial thrust bearing to prevent rotation thereof.
Additional advantages and features of the present invention will become apparent from the following description of the preferred embodiment taken in conjunction with the appended claims and drawings.